Radiotelegraphy



L. F. FULLER. RADIOTELEGRAPHY.

APPLICATION FILED SEPT 19, 1912' 1,352,886. Patented Sept. 14, 1920.

? MEMO/2 T L. E FULLER W/77VE66.

I TTORNE V5 nnrrso STATE?) rarest o LEONARD r. FULLER, or 'SAN raanorscocamroama, Assmnor. r0 rnniraat TELEGRAPH COMPANY, or sen FRANCISCO, oaltrroama, a coarse-arrest OF CALIFORNIA.

RADIOTELEGRAPHY.

Specification of Letters Patent.

Patented Sept. re, filth/iii.

system of radio telegraphy, and particularly continuous-oscillation radio telegraphy, involving variations in antenna inductance. ()ne widely used form of sig-' naling with continuous oscillations consists in varying the antenna inductance, either by short-ch uiting a portion of the antenna loading coil or by short-circuiting a compensation helix arranged in the antenna circuit. This variation in inductance produces a variation in wave length and to produce a given percentage change in wave length, the antenna inductance must be changed a certain amount. The antenna current through the inductance changed sets up a certain voltage, which, multipliedby the antenna current, gives the kilo-voltaniperes to be handled .by the key or relay or other signaling instrument. On, account of practical considerations, the kilo-voltamperes which can be handled by one pair of contacts is limited and hence it has been necessary. to employ a plurality of contacts. -An object of the present invention is to provide a system whereby the kilo-voltampereswhich can be successfully handled by one pair of contacts is greatly increased and consequently the number of contacts re duced to aminimum. A further object of the invention is to provide a system which makes the load on the key such that it can be successfully handled with air as the contact dielectric instead of making the contact dielectric suit the load, for example, by immersion in oil to reduce sparking.

Theinvention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where I shall outline in full, that form of the invention which I have selected for illustration in the drawings accompanying and forming part of the present specification. In said drawings T have shown one specific form of the app ratus of my invention, but it is to be understood that I do not limit myself to such form, since the invention expressed in the claims may be embodied in a plurality of forms. I Referring to said drawings: Figure 1 is a diagrammatic representation of a radio telegraphy transmission sys-' tern illustrating my invention.

Fig. 2 is a diagrammatic representation of the system of my invention when em ployed in very high powered-stations.

Fig. 3 is a cross section of the lower turn of the inductance and theloop.

I have found that the load which can be handled with one pair of contacts is limited mainly by the voltage and not by the current and by making the amperes high and the voltage low, a much greater load can be successfully handled byone pair of contacts. Heretofore, it has been the practice to employ a relay for opening and closing the short-circuit around the helix in the antenna circuit, and the relay was operated by a key in the local circuit. This necessitated insulating the "local circuit from the high potential oscillating circuit, and also permitted the contacts to operate only with the antenna current instead of with a higher current value. Therefore, less kilo-voltamperes could be handled by one pair of contacts, because the voltage was high, and the voltage across the contacts liniits the kilo-volt-ampere they can handle to a verv great extent. My invention overcomes these difficulties, permitting only a low po-' tential in the signaling circuit.

The ordinary continuous oscillation trans mission system may be represented by an are 2 supplied with current from the gene rator 3. One side of the arc is grounded and the other side is connected to the antenna t, through the variable inductance or loading coil 5. This is the usual form of arc radio transmission systems, so that it is unnecessary to enter irto the details thereof. i1

cuit and signaling is accomplished by openin and closing the relay.

11 very high powered stations, where the antenna current may be, for instance, 300

amperes and the loop current 600 amperes, it is impractical to endeavor to control the loop current with one pair of contacts, because the loop-reactive voltage becomes too high, and under such and similar conditions I provide means for employing a plurality of airs of contactsi so arranged that each pair andles a given oad, regardless of whether the contacts are closed simultaneously or in succession. To produce this result, I divide the loop into a plurality of segments 8, preferably of equal-length, by conductors 9 connected at one end to the loop at equally spaced points and connected together at the other ends. In each segment I insert a relay 7, the solenoids 12 of the relays being connected in series in the local circuit, with the key 13. This arrangement equalizes the loads on the pairs of contacts, so that extremely large loads may be handled. The loop 6 is preferably of the same diameter as the inductance coil 5 and is axially alined therewith and spaced apart from the lower turn of the coil a sufficient distance to provide for ample insulation of the locip from the coil. claim:

3. A radio telegraphy transmission sys- I tem including an antenna circuit, a stepdown transformer having its primary in the antenna circuit, a plurality of conductors short circuiting difi'eren-t sections of the transformer secondary, and means in the short-circuited sections for opening and closing the circuit through the said sections.

4. A. radio telegraphy transmission system including an antenna circuit, a stepdoWn transformer having its primary in the antenna circuit, interconnected conductors connected to spaced points on the transformer secondary, and means in the secondary between the points of connection of the interconnected conductors for opening and closing the secondary.

5. A radio telegraphy transmission system including an antenna circuit, an inductance coil in said circuit, a loop inductively associated with said coil, a plurality of interconnected conductors connected to the loop at spaced points and dividing the loop into-a plurality of segments, and means in each segment for opening and closing the circuit in each segment.

6. A radio telegraphy transmission system including an antenna circuit, an induc tance coil in said circuit, a loop inductively associated with said coil, a plurality of interconnected conductors connected to the loop at spaced points and dividing the loo-p into a plurality of segments, a switch in each segment and means for operating said switches.

7. A radio telegraphy transmission system including an antenna circuit, an inductance coil in said circuit, a loop inductively associated with said coil, a plurality of interconnected conductors connected to the loop at spaced points and dividing the loop into a plurality of equal segments, a switch in each segment and means for operating said switches. y

In testimony whereof, I have hereunto set my hand at San Francisco, California, this 11th day of September, 1917.

LEONARD F. FULLER.

In presence of H. G, Prom. 

